Atlanta-based Delta Air Lines has launched its first flights on Boeing 717s that came from competitor AirTran Airways.

The first 717 jets repainted in Delta colors with a new Delta 110-seat layout flew passengers from Atlanta to Newark at 7:30 a.m. and 10 a.m. on Friday morning. The planes flew back to Atlanta later in the day.

Delta struck the deal with AirTran parent Southwest Airlines last year to take over a total of 88 717s. Delta will use the planes to replace less-efficient 50-seat regional jets. Southwest wanted to divest the 717s it inherited through its 2011 AirTran acquisition in order to maintain an all-Boeing 737 fleet. Dallas-based Southwest is repainting the planes and making other modifications for Delta.

The launch of the 717 service by Delta was originally set for September, but was delayed after certification issues with the newly configured planes, involving items such as exit row tray tables.

Southwest will gradually transfer the 717s over to Delta over the next two years. Now that the shift of 717s has begun, the shrinking of AirTran will accelerate as service is taken over by Southwest, according to Southwest chief executive Gary Kelly.